The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Fuel cells have been developed for portable power applications to compete with portable generators, batteries, and other energy conversion devices. Fuel cells are advantageous over generators in that fuel cells can operate at higher fuel-to-energy conversion efficiency levels. In particular, a generator's efficiency is limited by an efficiency ceiling defined by the generator's thermal cycling. Because fuel cells convert a fuel's chemical energy directly to electrical energy, fuel cells can operate at efficiency levels that are much higher than generators at comparable power levels. Further, portable generator systems generally do not efficiently power and energy requirements for applications requiring low amounts of continuous power, for example less than one kilowatt of continuous power, wherein a fuel cell system can operate efficiently within this power range.
Portable fuel cell systems can meet power and energy requirements that are not met by either batteries or other energy conversion devices. For example, high-efficient lithium ion batteries can have more than ten times the weight-to-energy ratio as an energy equivalent fuel cell system inclusive of three days of fuel.
Improvements in performance and cost reduction will enable the large-scale adoption of fuel cells in the commercial marketplace. Areas for fuel cell performance improvement include fuel cell system weight improvements, fuel cell fuel efficiency improvements, and fuel cell durability improvements. Areas of cost improvements include reducing material costs, improving high volume manufacturing efficiency, decreasing fuel consumption, and decreasing operating costs.
The following description and figures sets forth a fuel cell system having improvements in performance and cost, which will progress adoption of fuel cell systems in the commercial applications.